This invention relates to programmable electronic cooking apparatus constructed to effect the cooking of food in accordance with a programmed cooking operation as in a microcomputer-controlled microwave oven.
Various electronic cooking apparatus constructed to effect a food cooking process under the control of a microcomputer according to a programmed cooking sequence, have been in practical use. In a microcomputer-controlled microwave oven, for example, a magnetron is deenergized from the safety standpoint immediately when the door of a cooking (heating) chamber is opened during cooking.
While the magnetron stops oscillating with the opening of the magnetron energizing circuit, the content of program stored in the microcomputer is not cleared at this time, but merely the progress of the program is interrupted. Thus, if the food taken out from the heating chamber by opening the door is not perfectly cooked yet, it may be returned into the heating chamber, and the interrupted cooking program may be resumed by closing the door again and then depressing a cooking switch button. On the other hand, if the food is perfectly cooked, it is no longer returned into the heating chamber, and the remaining programmed cooking operation remains without being cleared. In this case, if the cooking switch button is depressed by mistake after closing the door of the heating chamber again, which is empty at this time, the magnetron is operated in response to the remaining cooking program, for instance, a programmed temperature in a temperature cooking mode. Consequently, electromagnetic energy that is generated from the magnetron is not absorbed by any food in the heating chamber but is reflected by the inner chamber wall, thus giving rise to various problems such as the life reduction and characteristic deterioration of the magnetron, dissolving of parts and generation of spark. In the worst case, a fire hazard is prone.